[ISSUE][proton-j] session begin frame handler throws NPE

[Sreeram Kumar Garlapati <sr...@microsoft.com.INVALID>]

Hello Qpid developers!!

We are using proton-j Reactor APIs to and are hitting a NullPointerException – which is a TODO in the proton-j codebase 😊. Truly appreciate if someone can help complete the TODO.
Link to the line: https://github.com/apache/qpid-proton-j/blob/master/proton-j/src/main/java/org/apache/qpid/proton/engine/impl/TransportImpl.java#L1160

Here’s the scenario when our customers are hitting this:
·       - configure the listener - to delay respond to session.begin on an AmqpConnection for ex: by 5 secs
·       - then client (or another peer) sends session.begin to that listener
·       - client doesn't receive any response even after 1 sec (as delay of 5 secs was configured)
·       - then the client decides to close the session
·       - then, after few sec's service(listener) responds back with session.begin for that closed session
·
·       In this case TransportImpl.handleBegin (frameparser implementation) – bails out with NPE.
·
·       This is truly not such an uncommon scenario! Many a times, when our Service nodes are busy (high CPU or have large request queue length) – our clients are experiencing this.

Filed a JIRA for this: https://issues.apache.org/jira/browse/PROTON-1939

Thanks a lot for the help so far!
Sreeram